Mechanical responses and failure of fiber-reinforced polymer (FRP) composite
laminates could be predicted using the validated finite element (FE) simulation. The
material constitutive and damage models employed in the simulation are developed
based on the properties of the unidirectional lamina, including those obtained
through tension tests. Such computational model assumes perfectly aligned fibers in
the lamina. In this respect, this paper examined the effect of fabrication-inherited
fiber misalignment on the tensile response of the unidirectional lamina. For this
purpose, a series of tension tests are performed on unidirectional carbon fiberreinforced
polymer (CFRP) composite lamina specimens with different gage lengths
ranging from 50 to 150 mm. Fiber misalignment is quantified to be 7o and represents
the nominal deviation of the fibers from the reference longitudinal axis direction.
Load-displacement responses of the specimens are compared. Results show that the
nominal tensile strength of the lamina is 1089±33 MPa. The elastic modulus,
however, increases from 36.96 to 55.93 GPa as the gage lengths vary from 50 to 150
mm, respectively. This is due to the induced bending effects on the reinforcing fibers
that is greater for longer gage lengths. Multiple fiber fracture events, each is depicted
in a noticeable load drop, are recorded throughout the tensile loading of long lamina
specimens. Although the load at fracture is accurately reproduced by the FE
simulation using the damage-based mesoscale model, the effect of fiber
misalignment could not be captured.